/*
** $Id: lstate.h,v 2.24.1.2 2008/01/03 15:20:39 roberto Exp $
** Global State
** See Copyright Notice in lua.h
*/

#ifndef lstate_h
#define lstate_h

#include "lua.h"

#include "lobject.h"
#include "ltm.h"
#include "lzio.h"



struct lua_longjmp;  /* defined in ldo.c */


/* table of globals */
#define gt(L)   (&L->l_gt)

/* registry */
#define registry(L) (&G(L)->l_registry)


/* extra stack space to handle TM calls and some other extras */
#define EXTRA_STACK   5


#define BASIC_CI_SIZE           8

#define BASIC_STACK_SIZE        (2*LUA_MINSTACK)



typedef struct stringtable
{
    GCObject **hash;
    lu_int32 nuse;  /* number of elements */
    int size;
} stringtable;


/*
** informations about a call
*/
typedef struct CallInfo
{
    StkId base;  /* base for this function */
    StkId func;  /* function index in the stack */
    StkId top;  /* top for this function */
    const Instruction *savedpc;
    int nresults;  /* expected number of results from this function */
    int tailcalls;  /* number of tail calls lost under this entry */
} CallInfo;



#define curr_func(L)    (ttisfunction(L->ci->func) ? clvalue(L->ci->func) : NULL)
#define ci_func(ci) (ttisfunction((ci)->func) ? clvalue((ci)->func) : NULL)
#define f_isLua(ci) (!ttislightfunction((ci)->func) && !ci_func(ci)->c.isC)
#define isLua(ci)   (ttisfunction((ci)->func) && f_isLua(ci))


/*
** `global state', shared by all threads of this state
*/
typedef struct global_State
{
    stringtable strt;  /* hash table for strings */
    lua_Alloc frealloc;  /* function to reallocate memory */
    void *ud;         /* auxiliary data to `frealloc' */
    lu_byte currentwhite;
    lu_byte gcstate;  /* state of garbage collector */
    lu_byte gcflags;  /* flags for the garbage collector */
    int sweepstrgc;  /* position of sweep in `strt' */
    GCObject *rootgc;  /* list of all collectable objects */
    GCObject **sweepgc;  /* position of sweep in `rootgc' */
    GCObject *gray;  /* list of gray objects */
    GCObject *grayagain;  /* list of objects to be traversed atomically */
    GCObject *weak;  /* list of weak tables (to be cleared) */
    GCObject *tmudata;  /* last element of list of userdata to be GC */
    Mbuffer buff;  /* temporary buffer for string concatentation */
    lu_mem GCthreshold;
    lu_mem totalbytes;  /* number of bytes currently allocated */
    lu_mem memlimit;  /* maximum number of bytes that can be allocated, 0 = no limit. */
    lu_mem estimate;  /* an estimate of number of bytes actually in use */
    lu_mem gcdept;  /* how much GC is `behind schedule' */
    int gcpause;  /* size of pause between successive GCs */
    int gcstepmul;  /* GC `granularity' */
    int egcmode;    /* emergency garbage collection operation mode */
    lua_CFunction panic;  /* to be called in unprotected errors */
    TValue l_registry;
    struct lua_State *mainthread;
    UpVal uvhead;  /* head of double-linked list of all open upvalues */
    struct Table *mt[NUM_TAGS];  /* metatables for basic types */
    TString *tmname[TM_N];  /* array with tag-method names */
} global_State;


/*
** `per thread' state
*/
struct lua_State
{
    CommonHeader;
    lu_byte status;
    StkId top;  /* first free slot in the stack */
    StkId base;  /* base of current function */
    global_State *l_G;
    CallInfo *ci;  /* call info for current function */
    const Instruction *savedpc;  /* `savedpc' of current function */
    StkId stack_last;  /* last free slot in the stack */
    StkId stack;  /* stack base */
    CallInfo *end_ci;  /* points after end of ci array*/
    CallInfo *base_ci;  /* array of CallInfo's */
    int stacksize;
    int size_ci;  /* size of array `base_ci' */
    unsigned short nCcalls;  /* number of nested C calls */
    unsigned short baseCcalls;  /* nested C calls when resuming coroutine */
    lu_byte hookmask;
    lu_byte allowhook;
    int basehookcount;
    int hookcount;
    lua_Hook hook;
    TValue l_gt;  /* table of globals */
    TValue env;  /* temporary place for environments */
    GCObject *openupval;  /* list of open upvalues in this stack */
    GCObject *gclist;
    struct lua_longjmp *errorJmp;  /* current error recover point */
    ptrdiff_t errfunc;  /* current error handling function (stack index) */
};


#define G(L)    (L->l_G)


/*
** Union of all collectable objects
*/
union GCObject
{
    GCheader gch;
    union TString ts;
    union Udata u;
    union Closure cl;
    struct Table h;
    struct Proto p;
    struct UpVal uv;
    struct lua_State th;  /* thread */
};


/* macros to convert a GCObject into a specific value */
#define rawgco2ts(o)    check_exp((o)->gch.tt == LUA_TSTRING, &((o)->ts))
#define gco2ts(o)   (&rawgco2ts(o)->tsv)
#define rawgco2u(o) check_exp((o)->gch.tt == LUA_TUSERDATA, &((o)->u))
#define gco2u(o)    (&rawgco2u(o)->uv)
#define gco2cl(o)   check_exp((o)->gch.tt == LUA_TFUNCTION, &((o)->cl))
#define gco2h(o)    check_exp((o)->gch.tt == LUA_TTABLE, &((o)->h))
#define gco2p(o)    check_exp((o)->gch.tt == LUA_TPROTO, &((o)->p))
#define gco2uv(o)   check_exp((o)->gch.tt == LUA_TUPVAL, &((o)->uv))
#define ngcotouv(o) \
    check_exp((o) == NULL || (o)->gch.tt == LUA_TUPVAL, &((o)->uv))
#define gco2th(o)   check_exp((o)->gch.tt == LUA_TTHREAD, &((o)->th))

/* macro to convert any Lua object into a GCObject */

#define obj2gco(v)  (cast(GCObject *, (v)))

LUAI_FUNC lua_State *luaE_newthread(lua_State *L);
LUAI_FUNC void luaE_freethread(lua_State *L, lua_State *L1);

#endif

